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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.search.highlight;
import com.google.common.collect.ImmutableMap;
import org.apache.lucene.search.Query;
import org.elasticsearch.common.component.AbstractComponent;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.regex.Regex;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.mapper.DocumentMapper;
import org.elasticsearch.index.mapper.FieldMapper;
import org.elasticsearch.index.mapper.core.StringFieldMapper;
import org.elasticsearch.index.mapper.internal.SourceFieldMapper;
import org.elasticsearch.search.SearchParseElement;
import org.elasticsearch.search.fetch.FetchSubPhase;
import org.elasticsearch.search.internal.InternalSearchHit;
import org.elasticsearch.search.internal.SearchContext;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import static com.google.common.collect.Maps.newHashMap;
/**
*
*/
public class HighlightPhase extends AbstractComponent implements FetchSubPhase {
private static final List STANDARD_HIGHLIGHTERS_BY_PRECEDENCE = Arrays.asList("fvh", "postings", "plain");
private final Highlighters highlighters;
@Inject
public HighlightPhase(Settings settings, Highlighters highlighters) {
super(settings);
this.highlighters = highlighters;
}
@Override
public Map parseElements() {
return ImmutableMap.of("highlight", new HighlighterParseElement());
}
@Override
public boolean hitsExecutionNeeded(SearchContext context) {
return false;
}
@Override
public void hitsExecute(SearchContext context, InternalSearchHit[] hits) {
}
@Override
public boolean hitExecutionNeeded(SearchContext context) {
return context.highlight() != null;
}
@Override
public void hitExecute(SearchContext context, HitContext hitContext) {
Map highlightFields = newHashMap();
for (SearchContextHighlight.Field field : context.highlight().fields()) {
Collection fieldNamesToHighlight;
if (Regex.isSimpleMatchPattern(field.field())) {
DocumentMapper documentMapper = context.mapperService().documentMapper(hitContext.hit().type());
fieldNamesToHighlight = documentMapper.mappers().simpleMatchToFullName(field.field());
} else {
fieldNamesToHighlight = Collections.singletonList(field.field());
}
if (context.highlight().forceSource(field)) {
SourceFieldMapper sourceFieldMapper = context.mapperService().documentMapper(hitContext.hit().type()).sourceMapper();
if (!sourceFieldMapper.enabled()) {
throw new IllegalArgumentException("source is forced for fields " + fieldNamesToHighlight + " but type [" + hitContext.hit().type() + "] has disabled _source");
}
}
boolean fieldNameContainsWildcards = field.field().contains("*");
for (String fieldName : fieldNamesToHighlight) {
FieldMapper fieldMapper = getMapperForField(fieldName, context, hitContext);
if (fieldMapper == null) {
continue;
}
// We should prevent highlighting if a field is anything but a text or keyword field.
// However, someone might implement a custom field type that has text and still want to
// highlight on that. We cannot know in advance if the highlighter will be able to
// highlight such a field and so we do the following:
// If the field is only highlighted because the field matches a wildcard we assume
// it was a mistake and do not process it.
// If the field was explicitly given we assume that whoever issued the query knew
// what they were doing and try to highlight anyway.
if (fieldNameContainsWildcards) {
if (fieldMapper.fieldType().typeName().equals(StringFieldMapper.CONTENT_TYPE) == false) {
continue;
}
}
String highlighterType = field.fieldOptions().highlighterType();
if (highlighterType == null) {
for(String highlighterCandidate : STANDARD_HIGHLIGHTERS_BY_PRECEDENCE) {
if (highlighters.get(highlighterCandidate).canHighlight(fieldMapper)) {
highlighterType = highlighterCandidate;
break;
}
}
assert highlighterType != null;
}
Highlighter highlighter = highlighters.get(highlighterType);
if (highlighter == null) {
throw new IllegalArgumentException("unknown highlighter type [" + highlighterType + "] for the field [" + fieldName + "]");
}
Query highlightQuery = field.fieldOptions().highlightQuery() == null ? context.parsedQuery().query() : field.fieldOptions().highlightQuery();
HighlighterContext highlighterContext = new HighlighterContext(fieldName, field, fieldMapper, context, hitContext, highlightQuery);
if ((highlighter.canHighlight(fieldMapper) == false) && fieldNameContainsWildcards) {
// if several fieldnames matched the wildcard then we want to skip those that we cannot highlight
continue;
}
HighlightField highlightField = highlighter.highlight(highlighterContext);
if (highlightField != null) {
highlightFields.put(highlightField.name(), highlightField);
}
}
}
hitContext.hit().highlightFields(highlightFields);
}
private FieldMapper getMapperForField(String fieldName, SearchContext searchContext, HitContext hitContext) {
DocumentMapper documentMapper = searchContext.mapperService().documentMapper(hitContext.hit().type());
// TODO: no need to lookup the doc mapper with unambiguous field names? just look at the mapper service
return documentMapper.mappers().smartNameFieldMapper(fieldName);
}
}